The present invention generally relates to a system and a method for providing a global positioning system (GPS) enabled antenna.
A conventional hand-held global positioning system (GPS) device provides positional information about the location of the GPS device by receiving and processing GPS band signals from a GPS system including satellites and base stations. Although such positional information can be quite useful, it is not convenient to carry a conventional GPS device along with a multitude of mobile wireless communications devices such as laptops, mobile phones, PDAs, or other mobile devices on which users now depend. It is therefore desirable that a GPS positioning function be included with another device, such as a wireless mobile handset.
Unfortunately, the integration of GPS technology with other mobile wireless communications devices such as, for example, cellular or personal communications services (PCS) phones has proven difficult. In particular, three alternatives have been identified for adding GPS capability to a wireless device or handset, but have proven unsatisfactory in use.
A first choice is to add GPS capability in a wireless handset by adding a separate antenna for GPS reception. Since the wireless network antenna is not modified, network communications quality is not adversely affected. However, as mobile handsets for wireless networks have become much smaller, less space is available on the handset housing to accommodate a separate, custom-designed GPS antenna. Furthermore, a GPS antenna disposed within the handset housing typically suffers from a number of reception problems. For example, poor reception can be caused by electromagnetic shielding within the handset housing and by the handset housing itself. Adjusting the electromagnetic shielding to accommodate the GPS antenna may cause substantial redesign and testing of the handset. Even the hand of the user of the wireless handset may interfere with the reception by the internal GPS antenna as the user grips the handset housing. Also, adding a separate antenna and its associated circuitry to the wireless handset adds expense and design complexity.
A second choice is to add GPS capability to a wireless handset by enabling the existing network antenna on the wireless handset to adequately receive a GPS band signal. For example, a typical dual-band antenna may be constructed to receive a PCS signal at approximately 1900 MHz and a cellular signal at approximately 800 MHz. It may therefore be possible that the existing dual-band antenna may be able to receive a GPS signal at approximately 1575 MHz. However, the GPS signal is at a non-resonant frequency for the dual-band antenna, so the received GPS signal would be less than optimal resulting in degraded signal transfer. In this regard, known dual-band antenna systems are not able to receive a GPS signal with sufficient strength and quality to implement a robust GPS location functionality on a wireless handset.
A third choice is to add GPS capability to a wireless handset by using a tri-band antenna. A tri-band antenna is constructed to receive the cellular, PCS and GPS frequencies, for example. Although such an antenna enables the GPS signal to be received, due to the limitations of antenna design such an antenna normally compromises either the cellular or PCS performance, or both. Using a tri-band antenna also substantially adds extra cost to the antenna.
Accordingly, there exists a need to add GPS position location capability in a wireless handset in a robust, economical manner. Furthermore, it would be desirable that the GPS position location capability be provided in a convenient, aesthetically pleasing manner.
The present invention alleviates to a great extent the disadvantages of conventional systems and methods for providing a global positioning system (GPS) enabled antenna in a wireless communications device.
In an exemplary embodiment, a system and a method for providing a global positioning system (GPS) enabled antenna system are provided. The GPS enabled antenna may be used, for example, on a wireless communications device such as a wireless handset. The wireless communications device may include a switching module that can selectively switch communications signals between the antenna and one of a plurality of communications band circuitries. A respective impedance matching circuit may be provided between the switching module and particular communications band circuitry to match or to tune the antenna to the particular communications band circuitry.
Advantageously, the present invention enables an existing antenna in a wireless communications device to be adapted to robustly receive GPS band signals. Using the existing communications antenna to provide a GPS signal is a cost effective and efficient way to provide GPS position location functionality in a wireless communications device. Furthermore, phone aesthetics are unaffected as no separate GPS antenna is required. Adapting an existing antenna frees up space within the wireless communications device that otherwise might have been reserved for a separate and internal GPS antenna. In addition, since the existing antenna extends from the wireless communications device, the present invention benefits from improved reception of GPS band signals.
These and other features and advantages of the present invention will be appreciated from review of the following detailed description of the present invention, along with the accompanying figures in which like reference numerals refer to like parts throughout.